Direction control valves are available in many formats for controlling the flow of fluids between sources and applications. For mere on/off control, ball and poppet valves are effective and widely employed. Where flow rates, pressure drops, and other characteristics are desired, gate, butterfly, pressure regulating, needle control valves and other well know valve type are used. Combined with the need to handle diverse fluids, including gases, fluids, slurries of varying compositions, the number of available valves is substantial requiring dedicated tooling with little interchangeability of components.
In our pending patent application, U.S. Ser. No. 10/223,236 filed on Aug. 19, 2002, there is disclosed a flow control valve that can be manufactured in a wide range of valve sizes without dedicated tooling and requires minimal variations to handle gases and liquids at varying pressures and flow rates. Therein, a poppet valve assembly is carried in a two-piece valve body formed by conventional machining. The poppet valve assembly includes a non-spring biased piston isolated from fluid flow. The pilot actuated piston shifts a poppet valve to a closed position around a flow orifice to block fluid flow. Removing pilot pressure allows the fluid flow to shift the valve to an open position. The poppet valve accommodates flow orifices of varying sizes. Thus, by merely changing the orifice size, differing pressures and flow rates can be handled allowing a commonality of components. The valves could also be interconnected to provide multi-port functionality. Notwithstanding the increased flexibility and functionality, these poppet valves, like others, provide only on/off control at prevailing conditions in prescribed flow paths between ports. Control of vacuum applications was not possible.
It would accordingly be desirable to utilize the benefits of our above valve in applications of directional flow control not currently enabled.